The present invention relates to image reading apparatuses and image forming apparatuses.
Generally, apparatuses employing methods such as a secured original reading method, in which an original is secured to read an original image, or a moving original reading method, in which the original is caused to move to read an original image, are employed as image reading apparatuses provided in image forming apparatuses such as copiers, facsimile machines, and digital multifunction machines, and image reading apparatuses that are connected to a computer via a communications means such as a network.
Specifically, an image reading apparatus of a secured original reading method reads an image of an original placed on an original table using an original reading portion that moves toward one side of a sub scanning direction while scanning in a main scanning direction orthogonal to the sub scanning direction. Furthermore, an image reading apparatus of a moving original reading method reads an image of an original that is transported toward one side of the sub scanning direction at a predetermined original reading position using an original reading portion that is positioned in a fixed position while scanning in the main scanning direction orthogonal to the sub scanning direction.
For example, common conventional image reading apparatuses include a configuration in which, in an original reading portion provided with a light source unit, in which a light source that irradiates an original and a first mirror are arranged, second and third mirrors, an image forming lens, and a reduction-type image sensor such as a CCD (charge coupled device), reflected light of the original irradiated by the light source is caused to form an image on the image sensor from the first mirror, the second mirror, and the third mirror via the image forming lens, thereby reading an original image, and a configuration in which, in an original reading portion provided with a light source that irradiates an original, and a contact type image sensor such as a CIS (contact image sensor), reflected light of the original irradiated by the light source is caused to be incident on the image sensor, thereby reading an original image.
In reading an original with an image reading apparatus of the secured original method, ordinarily reading of the original image in the sub scanning direction commences after a preset sub scanning reading commencement time has passed from a predetermined scanning position at which the original reading portion scans toward one side of the sub scanning direction. For example, the sub scanning reading commencement time can be set to a time from the movement commencement of the original reading portion moving toward one side of the sub scanning direction, until arriving at an original prescribing edge of a first original guide, which prescribes a placement position of the original in the sub scanning direction. Furthermore, with an image reading apparatus of the secured original method, sometimes reading of the original image in the main scanning direction may commence after a preset main scanning reading commencement time has passed from a predetermined scanning position at which the original reading portion scans toward one side of the main scanning direction. For example, the main scanning reading commencement time can be set to a time from the scanning commencement of the original reading portion moving toward one side of the main scanning direction, until scanning to an original prescribing edge of a second original guide, which prescribes a placement position of the original in the main scanning direction.
When the original guides are installed at a factory, or when the original guides are adjusted or exchanged by an operator such as a service operator in image reading apparatuses of the secured original method, there are discrepancies among image reading apparatuses in the distance between the scanning position of the original reading portion and the original guide due to factors such as discrepancy in the installation position of the original guide and discrepancy of the components, and therefore ordinarily at a time of shipping from the factory or a time of component adjustment or component exchange by an operator such as a service operator, the reading commencement time is adjusted in response to that discrepancy.
On the other hand, in reading an original with an image reading apparatus of the moving original method, ordinarily reading of the original image is configured to commence after a preset sub scanning reading commencement time has passed from detection of a transport timing of the original on an upstream side from the original reading position in the transport direction of the original toward one side of the sub scanning direction (for example, detection of a downstream side edge (leading edge) of the original in the transport direction by an original detection portion such as an original detection sensor). For example, the sub scanning reading commencement time can be set to a time in which the leading edge of the original is transported from a detection position of the transport timing by the original detection portion until the original reading position by the original reading portion.
When the original detection portion and the original reading portion are installed at the factory, or when the original detection portion and the original reading portion are adjusted or exchanged by an operator such as a service operator in image reading apparatuses of the moving original method, there are discrepancies among image reading apparatuses in the distance from the detection position of the transport timing by the original detection portion to the original reading position by the original reading portion due to factors such as discrepancy in the installation position of the original detection portion and the original reading portion and discrepancy of the components, and therefore ordinarily at a time of shipping from the factory or a time of component adjustment or component exchange by an operator such as a service operator, the reading commencement time is adjusted in response to that discrepancy.
For example, these adjustments of the reading commencement time are carried out by transporting an adjustment sheet in the actual image reading apparatus to be adjusted (see JP H3-158066A).
For example, in image reading apparatuses of the secured original method, the sub scanning reading commencement time is adjusted so as to become a sub scanning reading timing adjustment time from movement commencement when the original reading portion moves toward one side of the sub scanning direction until detection of a difference between a brightness of the first original guide and a brightness of a first mark formed on at least an edge of the adjustment sheet in the sub scanning direction by the original reading portion. Furthermore, the main scanning reading commencement time is adjusted so as to become a main scanning reading timing adjustment time from scanning commencement when the original reading portion scans toward one side of the main scanning direction until detection of a difference between a brightness of the second original guide and a brightness of a second mark formed on at least an edge of the adjustment sheet in the main scanning direction by the original reading portion.
However, with image reading apparatuses of the secured original method, problems such as the following arise since the brightness (image density) of the original guide varies according to the product specifications.
FIG. 9 is a diagram for describing conventional adjustment of reading commencement timings based on first and second marks Q1 and Q2 on an adjustment sheet P whose placement position is prescribed by first and second original guides 331 and 332 in an image reading apparatus 100′ of the secured original method, and is constituted by FIG. 9A, FIG. 9B, and FIG. 9C. FIG. 9A shows a schematic lateral view thereof. FIG. 9B shows a schematic view as seen from above of the first and second original guides 331 and 332 whose brightness is comparatively dark (blackish). FIG. 9C shows a schematic view as seen from above of the first and second original guides 331 and 332 whose brightness is comparatively light (whitish).
In the image reading apparatus 100′ of the secured original method, the placement position of the original or the adjustment sheet P in the sub scanning direction Y is prescribed by the first original guide 331, which is arranged at an upstream side of the original in the reading direction Y1 of the sub scanning direction (direction of arrow Y in the diagram). Furthermore, the placement position of the original or the adjustment sheet P in the main scanning direction X may also be prescribed by the second original guide 332, which is arranged at an upstream side of the original in the reading direction X1 of the main scanning direction (direction of arrow X in the diagram).
The first mark Q1 is formed on at least a leading edge P′ of the adjustment sheet P in the sub scanning direction Y. Furthermore, the second mark Q2 is formed on at least an edge P″ of the adjustment sheet P in the main scanning direction X.
Each of the first and second original guides 331 and 332 is formed (see FIG. 9C) such that at least its surface has a brightness (a brightness (generally white) having a difference from the brightness of the marks Q1 and Q2 that is identifiable when read by the original reading portion 200) lighter than the brightness (generally black) of the first and second marks Q1 and Q2. This enables the image reading apparatus 100′ to identify a difference between the brightness of the first and second original guides 331 and 332 and the brightness of the adjustment sheet P using the original reading portion 200.
And, as shown in FIG. 9C, a sub scanning reading commencement time Ta is adjusted in the sub scanning direction Y according to the first mark Q1 on the adjustment sheet P.
Generally, in adjusting the reading commencement timing in the sub scanning direction Y using the adjustment sheet P, a time T1a for adjusting timing of sub scanning reading is measured, which is from a predetermined scanning commencement (see α1 in FIG. 9) in the sub scanning direction Y of the original reading portion 200 until when a difference between the brightness of the first original guide 331 and the brightness of the adjustment sheet P is detected by the original reading portion 200 (see β1 in FIG. 9). Based on the time T1a for adjusting timing of sub scanning reading that is measured in this manner, the sub scanning reading commencement time Ta is adjusted. For example, in a case where the sub scanning reading commencement time Ta is a time from a movement commencement α1 of the original reading portion 200 in the sub scanning direction Y until arriving at a boundary position β1 between an original prescribing edge 331a of the first original guide 331 and the original, the sub scanning reading commencement time Ta is adjusted so that the sub scanning reading commencement time Ta becomes the time T1a for adjusting timing of sub scanning reading obtained through measurement.
Furthermore, this may be configured such that a main scanning reading commencement time Tb is adjusted in the main scanning direction X according to the second mark Q2 on the adjustment sheet P.
Generally, in adjusting the reading commencement timing in the main scanning direction X using the adjustment sheet P, a time T1b for adjusting timing of main scanning reading is measured, which is from a predetermined scanning commencement (see α2 in FIG. 9) in the main scanning direction X of the original reading portion 200 until when a difference between the brightness of the second original guide 332 and the brightness of the adjustment sheet P is detected by the original reading portion 200 (see β2 in FIG. 9). Based on the time T1b for adjusting timing of main scanning reading that is measured in this manner, the main scanning reading commencement time Tb is adjusted. For example, in a case where the main scanning reading commencement time Tb is a scanning time from a scanning commencement α2 of the original reading portion 200 in the main scanning direction X until a boundary position β2 between an original prescribing edge 332a of the second original guide 332 and the original, the main scanning reading commencement time Tb is adjusted so that the main scanning reading commencement time Tb becomes the time T1b for adjusting timing of main scanning reading obtained through measurement.
In a configuration such as this, due to a relationship of a destination of a product or product specifications such as product design, there are products in which the brightness of the first and second original guides 331 and 332 is set to a brightness comparatively similar to the first and second marks Q1 and Q2 of the adjustment sheet P (see FIG. 9B). When this happens, there are cases where a difference between the brightness of the first and second original guides 331 and 332 and the brightness of the first and second marks Q1 and Q2 cannot be identified with the adjustment method of FIG. 9C.
In these cases, as shown in FIG. 9B, it is necessary to identify a difference between the brightness of the first and second original guides 331 and 332 and a brightness other than the first and second marks Q1 and Q2 of the adjustment sheet P.
It should be noted that in a case where a blackish first original guide 331 is used, a sub scanning direction Y edge 333a of a white standard board 333 may be read, which is arranged on an upstream side in the sub scanning direction Y from the original prescribing edge 331a of the first original guide 331, then a measured time t2a, which is from the sub scanning direction Y edge 333a of the white standard board 333 until the original prescribing edge 331a of the first original guide 331, may be determined in advance by testing or the like, and a scanning time ta1 may be measured, which is from the scanning commencement (for example, movement commencement) α1 of the original reading portion 200 until a time when a difference between the brightness of the white standard board 333 and the brightness of the first original guide 331 is detected by the original reading portion (see Y1 in FIG. 9), thereby setting the sub scanning reading commencement time Ta as a total time of the scanning time ta1 and the measured time ta2.
In any case, there is a problem that the control configuration for adjusting the reading timing of originals G must be changed for each product due to the varying brightness of the first and second original guides 331 and 332.
On the other hand, in image reading apparatuses of the moving original method, the sub scanning reading commencement time is adjusted so as to become a sub scanning reading timing adjustment time from detection by an original detection portion of a leading edge of an adjustment sheet that is transported by the original transport portion on an upstream side in the transport direction from the original reading position until detection of a difference between a brightness of a reading member, which is arranged on an opposite side from the reading side by the original reading portion through the original transport path and a brightness of a mark formed on at least an edge of the adjustment sheet in the sub scanning direction by the original reading portion.
With the image reading apparatus of the moving original method, problems such as the following arise since the brightness (image density) of the reading member varies according to the product specifications.
FIG. 10 is a diagram for describing conventional adjustment of reading commencement timings based on a mark Q1 on an adjustment sheet P transported in an image reading apparatus 100″ of the moving original method, and is constituted by FIG. 10A, FIG. 10B, and FIG. 10C. FIG. 10A shows a schematic lateral view thereof. FIG. 10B shows a schematic view as seen from below of a reading member 318 whose brightness is comparatively dark (blackish). FIG. 10C shows a schematic view as seen from below of a reading member 318 whose brightness is comparatively light (whitish).
In the image reading apparatus 100″ of the moving original method, a reading member 318 is provided on an opposite side from the reading side of the original reading position β1 with an original transport path 303 in between, and this is read by the original reading portion 200 at a non-transport time of the original.
The reading member 318 is formed (see FIG. 10C) such that at least its surface has a brightness (a brightness (generally white) having a difference from the brightness of the mark Q1 that is identifiable when read by the original reading portion 200) lighter than the brightness (generally black) of the mark Q1. This enables the image reading apparatus 100″ to identify a difference between the brightness of the reading member 318 and the brightness of the adjustment sheet P using the original reading portion 200.
And, as shown in FIG. 10C, a sub scanning reading commencement time Ta is adjusted in the sub scanning direction Y according to the mark Q1 on the adjustment sheet P.
Generally, in adjusting the reading commencement timing in the sub scanning direction Y using the adjustment sheet P, the time T1a for adjusting timing of sub scanning reading is measured, which is from detection by the original detection sensor 320 of downstream side (leading edge portion) edge P′ of the adjustment sheet P transported in the transport direction Y3 by an unshown original transport portion on an upstream side of the transport direction Y3 from the original reading position β1 until reading of the leading edge P′ in the sub scanning direction Y of the mark Q1 on the adjustment sheet P by the original reading portion 200. Based on the time T1a for adjusting timing of sub scanning reading that is measured in this manner, the sub scanning reading commencement time Ta is adjusted. For example, in a case where the sub scanning reading commencement time Ta is a time from detection of the leading edge of the original by the original detection sensor 320 until reading of the leading edge of the original by the original reading portion 200, the sub scanning reading commencement time Ta is adjusted so that the sub scanning reading commencement time Ta becomes the time T1a for adjusting timing of sub scanning reading obtained through measurement.
In a configuration such as this, due to a relationship of a destination of a product or product specifications such as product design, there are products in which the brightness of the reading member 318 is set to a brightness comparatively similar to the mark Q1 of the adjustment sheet P (see FIG. 10B). When this happens, there are cases where a difference between the brightness of the reading member 318 and the brightness of the mark Q1 cannot be identified with the adjustment method of FIG. 10C.
In these cases, as shown in FIG. 10B, it is necessary to identify a difference between the brightness of the reading member 318 and a brightness other than the mark Q1 of the adjustment sheet P.
Accordingly, there is a problem that the control configuration for adjusting the reading timing of originals G must be changed for each product due to the varying brightness of the reading member 318.
Thus, one issue of the present invention is to provide an image reading apparatus of a secured original method, in which the reading timing of an original can be reliably adjusted even when the brightness of the original guide varies due to product specifications without changing the control configuration for each product, and an image forming apparatus including this.
Furthermore, another issue of the present invention is to provide an image reading apparatus of a moving original method, in which the reading timing of an original can be reliably adjusted even when the brightness of the reading member varies due to product specifications without changing the control configuration for each product, and an image forming apparatus including this.